1. Field of the Invention
The invention relates to the field of x-ray inspection, more particularly to x-ray inspection of macroscopic phenomena such as stresses in a material.
2. Description of the Related Art
Moire inspection is widely known in use for inspection of areas accessible to visible light. X-rays are widely known for use in observation of areas that cannot be penetrated by visible light. Numerous methods for examining strain are available including electronic and optical strain gages and optical methods such as holography, shearography and speckle interferometry. The present invention allows for the inspection of areas that cannot be observed with optical methods. The interior of materials that are not transparent to visible light cannot be observed with the optical methods enumerated above.
Strain gages have two large limitations, the first is that they monitor only a single point, the second is the need for cables running from the gage to its accompanying electronics. It is sometimes impractical when examining the interior of structures to have cables leading from the interior to the exterior. It would be difficult to prevent leakage from a high pressure tire, for example, if there were a cable running from its interior. The first limitation can be overcome by constructing the pattern of this method such that it covers a large area of the inspected object. The second is overcome as the remote nature of this method allows for the elimination of any such cables,
There are some systems that make use of both x-rays and the Moire effect in diffraction measurements. These make use of reflection patterns to make measurements at the surface of a material. They are useful mostly on a very small scale and again fail to allow measurements at remote locations. The claimed method allows for remote measurements and large scale investigations.